Research On Animal Production

     The investigation was carried out to determine of chemical composition and dry matter, neutral detergent fiber (NDF) and crude protein (CP) degradability parameters of Kahoorak (Prosopis stephaniana) by using nylon bag technique. Plant samples were taken from the Sar Chah Amari of Khoosf in Birjand city. Samples were collected at three stages of plant growth (vegetative, fruiting and seeding stages) and fruit at two stages of growth (Fruiting and seeding). Four fistulated Brown Swiss heifers were used for determination of dry matter, CP and NDF degradability after incubation for 0, 2, 4, 8, 16, 24, 48 and 72 hours. Maximum CP of Prosopis stephaniana was in branches (13.24%) and plant fruit (10.88%) in vegetative stage. With advancing in plant growth CP and  tannin content was reduced but NDF and ADF content was increased. Degradation fractions (a and b) of CP in fruiting stage was more than seeding stage (p<0.05). The experimental results show that branches of Kahurak has optimum nutritive value compared with fruiting and seeding stages and with plant growth rate of ruminal fermentation and nutritive value of branches and fruits is reduced.